Small Machine Shops – 4 Things to Look For

Picking a small machine shop for your prototype work or limited production run can be confusing.  There is a wide spectrum from which to choose.  Your choice ranges between thousands on one-man-operations in small garages to shops employing a dozen people.  Which is right for you?  The following criteria will prepare you in choosing who you want to deal with.

1)   Types of Machinery
The defining characteristic of most shops is the type of machines they operate.   Be inquisitive.  Ask for an equipment list.  Many shops post this on their website.  Small shops usually pick one niche in which to operate, for example:  CNC vs. manual machines, milling or machining centers vs. turning, older machines vs. newest cutting-edge machines, prototype work vs. production, small parts vs. large parts.  Ask the shop owner or manager to define his business for you.  The capital costs involved prohibit owners from being all things to all people.  Most small machine shops can build almost anything given enough time and money.  However, selecting the right shop will save you time, money and frustration with only a little extra probing up front.

2)  Small Machine Shops Expertise
The shop owner has a mindset when approaching how his business operates.  Over the last thirty years there have been revolutionary improvements to the way shops approach their work.  You should be able to sense where the shop is in the manufacturing technology revolution by asking a few questions about how they handle a job as it moves through their operation.

For example:
Information Handling
Does the shop deal with sketches and paper drawings or are they comfortable accepting CAD drawing formats in 2D or solid models?  If you find a small machine shop that can only work from paper drawings you can reasonably assume a few more things.  They will likely not be able to make quick modifications to your design requests since they are using labor intensive techniques for machine operation, part programming, machine setup and inspection.  While there are exceptions, the ability to handle electronic drawings or solid modeling files gives a first indication of who you are dealing with.

QA Department
Ask if the shop has a dedicated QA manager with QA or QC control manuals.  The cost of setting up a QA department is high.  If your parts are to be used in the medical, aerospace, military, electronic or automotive arenas, you will likely need to work with shops with a dedicated QA department.   However, if your project in not destined for the high tech realm, you will be wasting some of your money in supporting a QA department that will add little to no value to your parts or product.

Age of Equipment
With small machine shops, ask the age of the newest large piece of equipment in the shop.  If the newest piece of equipment is older than eight years, you are dealing with a shop that has not kept pace with the latest developments in manufacturing and will not be able to handle extremely tight tolerance work.  While most machines can give good service for decades, many CNC machines are routinely replaced within ten years of being placed in service.  The reasons for this include: increased tolerance problems from ball screw wear, controller updates and improvements which outpace hardware improvements and bring new features for more efficient use.  Maintenance costs and down time come with age and these costs will eventually overtake the cost of machine replacement.  Break downs will sometimes affect scheduling and delivery dates in a shop with very old machinery.  Machine communication enhancements such as Ethernet connection, tool breakage detection and other improvements will be missing from shops with older machines.  Your goal should be to try to match the general quality of the shop’s machine tools to your part requirements.  If your parts don’t require state of the art manufacturing, you should not necessarily select a shop that can offer cutting edge manufacturing capacity.  You will essentially be subsidizing increased quality manufacturing for the customers that require it.

3)  Top Three Customers
Ask who their top three customers are and what kind of business they are in.  Also, ask how many years they been dealing with these three customers.  Their top customers should be a general reflection of the business you are in or are trying to become.  Does it make sense that their top customers are all in the electronics industry and your parts are headed for farming or agricultural use?  All shops will have this information on the tip of their tongue.  It’s worth your time to ask the question.  If their top customers have dealt with them for years, you can be assured that they are doing something right.  If your parts are headed into the same arena as their top customers, you can be assured that you are talking to the right shop for your products.

4)  Parts Cleaning
When evaluating small machine shops, ask how the parts are cleaned after manufacturing.  This will give you more insight into their operation than almost any other.  A shop owner’s approach to quality will almost always be exemplified in their choice of part cleaning equipment or their decision to cut corners in an area that is seldom asked about.  A finished part cleaning operation is moderately expensive to install and is almost never talked about by anyone until there is a problem with chips, grease oil or dirt adhering to parts.  There is probably no good reason to deal with a shop that has inadequate part cleaning facilities.  An inadequate part cleaning operation demonstrates the shop owner’s internal guidance system when it comes to producing a quality product.

These suggestions can help you avoid costly time delays and overcharges and are based on decades of experience.

Do you still need a machine shop?  Post your machining job at http://www.contractauction.com and watch manufacturer bids roll in.